Synthetic leathers based on poly (vinyl chloride) resins (PVC), and polymer alloys thereof, are extensively used in the automotive and furniture markets due to their low cost and durability (resistance to ozone, ultraviolet radiation, and burning) relative to natural leathers. Protective treatments have been developed for the purpose of cleaning, preserving, and conditioning the surfaces of these PVC products, as well as those fabricated from various organic rubbers and natural leathers. Specifically, polydimethylsiloxane oils have been used as treating agents for plastics and rubbers. Such treatments impart improved gloss, restore the appearance, and protect the surfaces against grease, dirt, water, UV radiation, thermal degradation and ozone. Thus, for example, U.S. Pat. No. 3,956,174 to Palcher discloses a process for protecting, preserving and renewing surfaces, such as rubber or polymer surfaces, the process comprising applying an emulsion of a polydimethylsiloxane fluid to the surface, allowing the fluid to penetrate the surface for a given time and then reiterating the application at least one more time. Preferred treating emulsions according to this patent include a polyol compound, such as diethylene glycol or glycerin.
Unfortunately, treatment with silicone compositions typically also has an undesirable side effect. These materials impart a "greasy" feel to the treated substrate. This greasiness is believed to be due to residual material which does not penetrate the surface and can subsequently attract dirt or dust.
Another problem associated with the typical silicone formulations is the high gloss imparted to the treated surface. This is especially problematic in current model automobiles and minivans which have large dashboards and windscreens. Excessive gloss of the treated surfaces can result in hazardous driving conditions due to the associated glare. This is especially the case during daylight hours when bright sunlight reflects off the treated dashboard, resulting in visual "washout" or temporary "blinding" of the driver. Although the glare issue in these critical automotive applications has been addressed by making use of plastic materials having lower gloss or matte finishes, these materials still require some aftermarket care in order to protect the original finish and restore the appearance of aged components. On the other hand, a slight enhancement of gloss is desired since this provides an immediate visual indication of the applied treatment for the consumer. Thus, a successful treating composition must have a delicate balance of gloss augmentation.